US3546991A - Skip feed control for perforating machines - Google Patents

Description

United States Patent Albert C Johnston. Roben E. lsner. Lewis H. Eslinger and Alvin Sinderbrand ABSTRACT: A perforating press or other machine performing repetitive operations on incrementally advanced sheet or strip-like material is provided with a skip feed apparatus by which various skip feeds or advances of the material are effected in a selectively predetermined sequence after certain numbers of such repetitive operations so that various patterns of the perforations or other operations on the material can be automatically obtained. The skip feeds are effected by a driving means in the form of a fluid pressure operated cylinder having its stroke limited by several adjustably located stops which are selectively disposed in operative or retracted positions to determine the extent of the skip feed resulting from each cylinder operation. Operation of the driving cylinder and positioning of the stops are controlled by a sequence circuit which includes a stepping relay actuated upon each operation of the cylinder to sequentially include in the circuit stop selector switches each set to cause a selected one of the stops to be disposed in its operative position and, following a predetermined number of operations of the press or other associated machine, operation of such machine is momentarily halted and the drive cylinder is operated to effect a skip feed corresponding to the selected stop. The number of machine [56] References Cited- UNITED STATES PATENTS XX 1 34 2 ll 36 82 PATENTED urn rs I976 SHEET 1 BF 3 E SNw REL Vl 08R E D mum m irt 0 1.. w V O U S m D A on v U MG VS 7 PATENTED um 5 I976 SHEET 3 OF 3 9E 5w at $5 INVENTORS JACK SWENDSEN SIGURD OWEN ROGDE ATTORNEY T mm.

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This invention relates to apparatus for feeding sheet or strip-like material to a machine, such asa perforating press, performing repetitive operations on the material, and more particularly to skip feeding apparatus by which, at selected intervals, the advance of the material can be increased beyond 1 the incremental advances effected in connection with the norobtain .the desired spacing between successive perforations or other operations performed on the material, and further by which either large or small incremental advances can be selected. Thus, it is possible to provide'patterns of perforations in which groups of perforations are closely spaced in correspondence with the small incremental advances and such groups are spaced from each other by imperforate areas or by groups of perforations that are widely spaced in correspondence with the large incremental advances. However, the patterns of perforations thus obtainable are limited by reason of the fact that only two feeding distances are available for the incremental advances, and also by reason of the fact that the frequency and order of the change from one feeding distance to the other cannot be conveniently varied.

Accordingly, it is an object of this invention, to provide apparatus for the feeding of sheet or strip-like material to a perforating or other machine performing repetitive operations on the material, and by which widely varying patterns of the per forations or the like can be conveniently and automatically obtained.

Another object is to provide an apparatus for the skip feeding of the material to the perforating or other repetitively operative machine during intervals when such machine is inoperative so as to provide spacing between groups of perforations or the. like. formed by operation of the machine, and wherein different skip feeds can be selected for the successive operations of the apparatus and the order'orsequence'with which the different skip feeds occur is also conveniently changeable.

Still another'object is to provide a skip feed apparatus, as above, with which the numbers of repetitive operations performed by the perforating'or other associatedmachine in the periods between successive skip feeds can be varied throughout the operating'cycle or sequence;

In accordance with an aspect of this invention, the skip feeds are effected by a driving means, preferably in the form of a fluid pressure operated cylinder having its stroke, and hence the extent of the resulting skip feed,lir nited during each cylinder operation by one of several adjustably located stops which are selectively disposed in operative or' retracted positions.

It is a feature of this invention to control the selective positioning of the stops by means of a sequencing circuit including a stepping relay which is stepped or actuated at the conclusion of each cylinder operation to sequentially activate stop-selector switches each set to cause a selected stop' to beoperative upon activation of the respective selector switch, whereby the successive skip feeds can be altered merely by changing the settings of the stop-selector switches and/or by adjusting the locations of the stops.

It is another feature of the invention to provide a plurality of .counting devices each operative to momentarily halt opera- SKIP FEED CONTROL FOR PERFORATING MACHINES tor switches also selectively activated in sequence by the I stepping relay and each being set to render operative a selected one of the counting devices when the respective count-selector switch is activated, whereby the numbers of repetitive operations occurring in the periods between successive skip feeds can be changed merely by changing the settings of the count-selector switches.

The above, and other objects, features andadvantages of this invention, will be apparent in the following detailed description of an illustrative embodiment which is to be read in connection with the accompanying drawings, wherein:

FIG. 1 is a schematic top plan view of a perforating press or machine repetitively perforating strip-like material as the latter is incrementally advanced therethrough and which is provided with a skip feed apparatus in accordance with an embodiment of this invention;

FIG. 2 is an elevational view of a drive unit included in the skip feed apparatus, and which is shown partly broken away;

FIG. 3 is a vertical sectional view taken along the line 3-3 on FIG. 2;

FIG. 4 is a horizontal sectional view taken along the line 4-4 on FIG. 2; and

FIG. 5 is a wiring diagram of sequencing and control circuits included in the apparatus of this invention.

Referring to the drawing indetail, and initially to FIG. 1 thereof, it will be seen that a perforating press 10 to which this invention may be applied generally comprises a press bed 11 above which a punch or die 12 is vertically reciprocable. During normal operation of press 10, sheetor strip-like material M is incrementally advanced while punch 12 is elevated and, in each dwell period between successive advances, punch 12 is stroked downwardly to perforate the material and then returned to its elevated position for the next incremental advance or feed of the material. Such normal incremental advancement of material M through press 10 may be effected by a feed roll 13 which is incrementally or intermittently turned in the direction to advance the material by a feed drive unit 14 which may be of the type disclosed in the aforesaid U.S. Pat. No. 3,338,491 and which is coupled to the shaft 15 of roll 13 by a one-way clutch 16.

Thus, during the normal repetitive operation of press 10, punch 12 of the latter forms perforations P in laterally extending rows, which rows are spaced by the distance d corresponding to the incremental advance of the material effected by drive unit 14.

In accordance with this invention, there is provided a skip feed apparatus 20 comprising a skip feed drive unit 21 which is coupled to shaft 15 through a one-way clutch 22, for example, of the sprag type, to effect turning of roll 13 in the direction for feeding material M at selected times when normal repetitive operation of press 10 and also of drive unit 14 is momentarily halted, as hereinafter described.

As shown on FIGS. 2 and 3, skip feed drive unit 21 includes an upstanding housing 23 provided with a base 24 bolted or otherwise secured to a suitable support 25, for example, constituted by an extension of press bed 11, as shown. Base 24 and support 25 are formed with aligned openings, as at 26 FIGS. 3), to permit the extension upwardly into housing 23 of the vertically reciprocable ram or piston rod 27 of a cylinder 28 depending from support 25. A vertical gear rack 29 is suitable secured, at its lower end, to ram 27 so as to be disposed in its lowermost position, as shown, when ram 27 is retracted and to move upwardly in housing 23 in response to extension of ram 27.

Shaft 15 of feed roll 13 extends through housing 23 and within the latter carries a pinion 30 which meshes with gear rack 29. Pinion 30 is mounted, as on a bearing 31, so as to be rotatable relative to shaft 15, and a tubular shaft 32 which is telescoped over shaft 15 and fixed to pinion 30 extends axially from the latter to clutch 22 to constitute the driving member of that clutch while shaft 15 is the driven member thereof.

, One-way clutch 22 is suitable arranged to drive shaft 15 and a feed roll 13 in the clockwise direction, as viewed on FIG. 2,

when pinion 30 is rotated in that direction in response to downward movement of rack 29 to the position shown. On the other hand, clutch 22 slips when pinion 30 is rotated counterclockwise in response to upward movement of rack 29, or when shaft and feed roll 13 are rotated by drive unit 14 to effect the normal incremental advances of the material.

The rack 29 is held in meshing engagement with pinion 30 and guided in its vertical movement by slidable engagement with a bearing block 33 which is adjustably positioned in housing 23, as by set screws 34 and 35.

It will be apparent that the extent of the skip feed of material M effected during each operation of drive unit 21 is determined by the length of the downward stroke of rack 29, that is, by the distance the rack moves downwardly until it reaches its lowermost position, as shown. Thus, the distance through which material M is advanced during each skip feed by apparatus can be varied by suitably changing the length of the downward or driving stroke of rack 29 with ram 27. In the illustrated embodiment of the invention, the length of each downward or driving stroke of rack 29 is controlled by selectively limiting the position to which the rack can be displaced during its upward or return stroke.

Such selective limitation of the return stroke of rack 29 with ram 27 is effected by four stop assemblies 36a, 36b, 36c and 36!! (FIGS. 2, 3 and 4) which are adjustable vertically, that is, parallel to the direction of reciprocation of rack 29, and selectively operative to limit the upward movement of the upper end of rack 29 at a location corresponding to the vertical location of the respective stop assembly. Thefour stop assemblies 36ad are vertically guided in a frame 37 constituted by vertical corner posts 38 extending from a top wall 39 of housing 23 and beingjoined, at their upper ends, to a top plate 40. Wall 39 has a central opening 41 (FIG. 3) through which rack 29 extends, and the .upper end of the latter has a head 42 secured thereon and shaped to slidably engage and be guided by comer posts 38 (FIG. 4).

Each of stop assemblies 36ad includes a body 43 which is vertically slidable and extends between two of corner posts 38, with the inner end of each body being shaped and dimensioned to clear head 42. Each body 43 has a horizontal slot 44 extending longitudinally therethrough (FIG. 3) to open at the inner and outer ends of the body, and a stop member 45 is longitudinally slidable in each slot 44 for movement between a retracted position, as shown for the stop member 45 of stop assembly 36b on FIG. 3, and an operative position, as shown for the stop member 45 of stop assembly 36d. In its retracted position, stop member 45 is wholly contained within the respective body 43 and thus is withdrawn from the path of travel of head 42.In its operative position, the inner end portion of stop member 45 projects beyond the inner end of body 43 into the path of travel of head 42 and thus restricts or limits the upward movement of rack 29 at the respective vertical location of the stop assembly having its stop member in operative position. The movements of each stop member 45 to its operative and retracted positions may be pneumatically or electrically controlled, for example, as shown, by a solenoid 46 mounted on the outer end of the respective body 43 and having its armature connected to the outer end of stop member 45, as at 47 (FIG. 3). Each solenoid 46 may be of the type which retracts its armature, as by an internal spring, when the solenoid is deenergized, whereby to move the respective stop member 45 to its retracted position, and which extends its armature when the solenoid is energized, whereby to move the stop member to its operative position.

The stop assemblies 36ad may be individually adjusted along corner posts 38 to vary their vertical locations on frame 37 by means of respective jack screws 48 which extend vertically in frame 37 and are mounted for rotation in wall 39 and top plate 40. Each jack screw 48 extends through, and is th 'readably engaged in threaded bores provided in the respective body 43 above and below slot 44 of the latter. Each stop member 45 has a longitudinally elongated slot 49 intermediate its ends and opening at the top and bottom surfaces of the stop member (FIG. 3) to permit the free passage therethrough of the jack screw 48 without interference from the latter with the movement of the stop member between its operative and retracted positions.

It will be apparent that rotation of each jack screw 48, as by a handle or socket wrench 50 engageable with a noncircular extension 51 of the jack screw projecting above top plate 40, will be effective to vertically displace the respective body 43 and thereby alter the location of the respective stop assembly. Before commencing operation of the skip feed apparatus 20, stop assemblies 36ad are adjusted, as described, so as to be at vertical locations corresponding to the lengths of skip feeds that are to be effected in any desired sequence. Thereafter, during successive operations of apparatus 20, the skip feeds in the desired sequence can be achieved merely by energizing the solenoids 46 of the respective stop assemblies one-at-atime in such sequence, for example, as by the sequencing and control circuits that will now be described with reference to FIG. 5.

As shown, such sequencing and control circuits may comprise a two-pole stepping relay switch 52, six stop-selector switches 53-1 to 53-6, six count-selector switches 54-1 to 54-6, four counting devices 55-] to 55-4, a counting switch 56, and a limit switch 57. j

The stepping relay switch 52 may be of a type having two poles 52a and 52b which are coupled so as to be stepped together to successively engage contacts numbered 1-6 in respective contact sets 52c and 52d. The stepping relay switch has a stepping coil 52e which, upon each energization thereof, advances poles 52a and 52b by one step, and a reset coil 52] which, upon its energization, is effective to return poles 52a and 52b to their initial or starting positions, as shown. Relay coil 52:: further controls contacts 52e-l and 52a-2 which are normally closed, as shown, and opened upon energization of the respective relay coil, and relay coil 52f further controls normally closed contacts 52f-1 which are opened upon energization of the respective coil.

As shown, contacts 526-1 and 52f-l are interposed in series between pole 52a and power supply line L so that a contact of set 52c can be energized only when contacts 52e-I and 52f-1 are simultaneously closed, that is, when neither coils 52e nor coil 52fis energized to step or reset stepping relay switch 52. Limit switch 57, which is normally open, is shown interposed in series with ON contacts a of a three-position switch 58 and with relay coil 52e between power supply lines L, and L so that, so long as switch 58 is in its ON" position as shown in full lines, relay coil 52e is energized to step switch 52 upon each closing of limit switch 57.

As shown particularly on FIG. 2, limit switch 57 is suitably mounted on housing 23 so as to be engaged and have its contacts closed, as by an actuating member 59 extending from rack 29, whenever cylinder ram 27 is fully retracted to dispose rack 29 in its lowermost position. Thus, assuming that the normal or starting position of rack 29 is an elevated position at which head 42 rests against one of stop members 45 disposed in its operative position, then it will be apparent that limit switch 57 is actuated to its closed position at the end of each downward operating stroke of rack 29 to cause stepping of stepping relay switch 52.

Three-position switch 58 further has contacts b which are open in the ON position of the switch and adapted to be closed in a RESET" position, at which position contacts a are opened. Contacts b of switch 58 are connected in series with relay coil 52f between lines L and L so that coil 52f is energized to return poles 52a and 52b to their initial positions whenever switch 58,is manually moved to its "RESET position. The third position of switch 58 is an OFF position, as shown in broken lines on FIG. 5, where contacts a and b are simultaneously open.

Each of the six stop-selector switches 53-1 to 53-6 has a manually movable selector contact 53a electrically connected with a respective one of the contacts 1-6 of contact set 52c.

The selector contact 53a of each of the stop-selector switches is selectively engageable with any one of six fixed contacts which are identified as contacts 1, 2, 3 and 4, reset contact and stop" contact, respectively. The. fixed; contacts numbered 1, 2, 3 and 4 of each of the stop-selector switches are shown respectively connected to one side of coils S-l,'S-2,

S-3 and S-4, which at their other side are electrically connected to supply line L,. The coils indicated at 8-1, S-2, S-3 andS-4 are respectively the coils of the solenoids in stop assemblies 36a, 36b, 36c and 36d. The reset contacts of stopselector switches 53-1 to 53-6 are connected'in a parallel circuitwith each other, and such parallel circuit is connected in series with contacts 52c-2 and reset relay coil 52f to supply line L The stop contacts of the stop-selector switches are similarly connected in a parallel circuit with each other, and such parallel circuit is connected in series withthe coil of a stop" relay 60 to supply line L Relay 60 is provided to stop the operation of the'associated perforating press when the coil of relay 60 is energized and, for that purpose, relay 60 may have normally closed contacts 60-1 interposed in a circuit, as shown, extending to a pressstop circuit 61. Whenever relay 60 is energized to open its contacts 60-1, the circuit 61 functions to stop the operation of press 10 with the punch or die 12 of the latter in its raised position. v

Each of the six count-selector switches 54-1 to 54-6 has a manually movable selector contact 54a electrically connected with a respective one of the contacts L6 in contact set 52:1. The selector contact 540 of each count'xselector switch is selectively engageable with any one of four fixed contacts which are identified as contacts 1, 2, 3 and 4. The fixed contacts 1, 2, 3 and 4 of each count-selector switch are respectively connected to counting devices 55-1, 5'5-2, 55-3 and 55-4, as shown, and such counting devices are connected in a parallel circuit which is connected to pole 52b of stepping relay switch 52 by way of the normally open counting switch 56;

The-counting devices 55-1 to 55-4 may be of a conventional electromechanical type having normally closed output relay contacts 550 which are opened for a short period, such as, a minimum period of 1025 seconds, when the respective counting device has detected the occurrence of a preset number of closings of switch 56, whereupon the counting device is automatically reset to close its contacts 55a and to recommence its counting operation.

The contacts 550 of counting devices 55-1 to 55-4 are connected in series with each other and with the coil of a relay 62 in a circuit which also extends to press stop circuit 61 so that relay 62 will be deenergized and circuit 61 will be caused to momentarily halt the operation of press 10 whenever any one of contacts 55a is opened and until such contacts are again closed by the automatic resetting of 1 the counting device. Relay 62 has contacts 62-1 which ;are."n'orrnally open, as shown, and closed when relay 62 is energized. Thus, contacts 62-1 remain closed until one of contacts 554 is opened. Contacts 62-1: are connected in series with a solenoid valve SV and a manually controlled switch 63 in a circuit between lines L, and L lt will be apparent that solenoid valve SV is energized only when switch 63 and contacts 62-1 are closed simultaneously.

Solenoid valve SV suitabletcontrols the supplying of compressed air or hydraulic fluid under pressure to cylinder 28 so that, when solenoid valve SV is energized, the fluid under pressure acts in cylinder 28 to extends its ram 27 and, when solenoid 28 is deenergized by the opening ofthe switch 63 or the opening of contacts 62-1, the fluid under pressure acts in cylinder 28 to retract its ram 27 andythereby effect the downward driving stroke of rack 29. f

The counting switch 56 is intended to be closed once during each of the repetitive perforating or other operations performed by press 10. Such cyclic closing of switch 56 may be effected, as shown,' by acam 64 which may be secured on the crankshaft 65 of press 10 to effect a revolution duringeach operating cycle of the press. It will be apparent that,'upon each closing of switch 56, a circuit is completed through that one of the counting devices 55-1 to 554 connected to the selected-fixed contact of that one of the count-selector switches 54-1 to 54-6 which has its movable contact 54a connected to the contact of set 52d then engaged by pole 52b of the stepping relay switch. The counting devices 55-1 to 55-4 have internal circuits and power supplies (not shown) so that, when a circuit is completed through a counting device, as described immediately above, an electrical pulse is detected in response to the closing of switch 56.

Six pilot lights 66-1 to 66-6 are connected between supply line L and the electrical connectionsto the movable contacts 53a of stop-selector switches 53-1 to 53-6, respectively, so as to be selectively illuminated when the respective stop-selector switch has its movable contact connected to supply line L,, through the respective contact of set 52d and pole 52b of the stepping relay switch. Thus, the illuminated pilot light indicates that step in the six-step sequence at which the sequencing circuit is positioned at any time during operation of the skip feed apparatus. It will be apparent that the six stopselector switches 53-1 to 53-6 respectively determine whether any one of the stop members 45' is to be moved to its operative position for the respective step or the six-step sequence, or whether the preceding steps of the sequence are to be repeated after the respective step by resetting of stepping relay switch 52, or whether the sequence is to be halted after the respective step by energizing of relay 60. Similarly, the six count-selector switches-544 to 54-6 respectively determine which of the counting devices 55-1 to 55-4 is to be operative during the respective step of the six-step sequence, thereby to determine the number of repetitive operations of press 10 which are to occur before the operation of cylinder 28 for'effecting a skip feed; Obviously, the several counting devices are suitably preset to count different numbers of repetitive operations.

The above described skip feed apparatus 20 according to this invention is operated as follows:

1. Switch 63 is moved to its open or manual" position, as shown, whereby to deenergize solenoidvalve SV and thus cause cylinder 28 to retract its ram 27 for moving rack 29 to its lowermost position so that the several stop assemblies 36a-36d can be adjusted to the locations corresponding to desired lengths of skipfeeds. As shown on FIG. 2, the body 43 of each stop assembly may have an index 67 extending therefrom to cooperate with a scale 68 on an adjacent corner post 38 for directly indicating the length of skip feed for which the respective stop assembly is set.

2. The switch 58 is first moved to its RESET" position to close its contacts b and open its contacts a, whereby to energize relay coil 52f so that poles 52a and 52b are returned to their initial positions where they engage the contact 1 of sets 52c and 52d, respectively. Then, switch 58 is moved to its OFF" position to open its contacts a and b.

3. With switch 58 in its OFF" position, the stop selector switches 53-1 to 53-6 and the count-selector switches 54-1 to 54-6' are set to provide for the desired lengths of skip feeds at the respective steps and the resetting or stopping of the cycle at the desired step of the sequence, and to provide for the desired numbers of repetitive operations of press 10 before therespective skip feeds.

. Having set the stop and count-selector switches, switch 63 is closed or disposed in its AUTOMATIC" position, whereby to energize solenoid valve SV so that cylinder 28 extends its rams 27 and thus moves'rack 29 upwardly against the stop meniber 45 which has been selected to be in its operative position by stop-selector, switch 53-1.

5. The sheet or striplike material to be perforated is fed I manually past feed roll 13 and under punch or die 12.

6. Switch 58 is moved to its ON" position to close its contacts a, and then operation of the press 10 is started. If the'stop and count-selector switches are set as shown on FIG; 5, the operation of press 10 andskip-feed apparatus 20 will proceed as follows:

a. Press 10 will repetitively operate on the material to provide the number of rows of perforations determined by counting device 55-2 selected by the setting of countselector switch 54-1. When the completion of such number of rows of perforations is detected by device 55-2, the latter opens its contacts 55a to interrupt the circuit to relay coil 62 and to cause the circuit 61 to halt the operation of press 10 with die 12 in its raised position. Deenergizing of coil 62 opens its contacts 62-1 and thereby deenergizes solenoid valve SV so that cylinder 28 retracts its cam 27 and causes the downward driving stroke of rack 29. Since the head 42 of rack 29 has been resting against stop member 45 of stop assembly 36d which is operative by reason of the energizing of solenoid coil S-4 through stop selector switch 53-1, the length of the downward driving stroke of rack 29, and hence the length of the resulting skip feed, is determined by the vertical position at which stop assembly 36d had been previously set. When ram 27 reaches the end of its retracting or driving stroke, limit switch 57 is closed to energize stepping coil 52e, whereby poles 52a and 52b are stepped or displaced into engagement with contacts 2 of sets 52c and 52d, respectively. The engagement of pole 5211 with contact 2 of set 520 activates stop-selector switch 53-2 and, by reason of the setting of the latter, solenoid coil 8-4 is deenergized and solenoid coil 8-1 is energized for moving stop member 45 of stop assembly 36a to its operative position and retracting the stop member of assembly 36d. When relay coil 62 is again energized by the closing of contacts 55a of counting device 55-2, contacts 62-1 close to energize solenoid valve SV so that cylinder 28 extends its ram 27 and thereby moves head 42 of rack 29 into engagement with the operative stop member of assembly 36a. The closing of contacts 550 of counting device 55-2 also causes press stop circuit 61 to restart press 10.

b. The press will continue its repetitive operation on the material for the number of rows of perforations for which counting device 55-1 is preset by reason of the selection of that counting device by count-selector switch 54-2 connected with contact 2 of set 52d. Upon the completion of that number of repetitive operations, contacts 55a of counting device 55-1 open momentarily and, as previously described, cause stoppage of the press and an operating or driving stroke of ram 27 and rack 29 through the distance determined by the location of operative stop assembly 36a. At the completion of such driving stroke which produces a corresponding skip feed, limit switch 57 closes to cause stepping of poles 52a and 52b to the third position, that is, into engagement with contacts 3 of sets 52c and 5211. Since the third stop-selector switch 53-3 is set for the same stop as stop-selector switch 53-2, solenoid coil S-l remains energized and stop assembly 36a continues to be operative to arrest the movement of rack 29 on its upward return stroke. When contacts 550 of counting device 55-1 again close, operation of press 10 resumes.

c. Since the third count-selector switch 54-3 is set to selectcounting device 55-3, the repetitive operations of the press driving the third step of the sequence continue for the number of operations determined by'counting device 55-3, whereupon contacts 55a of the latter open to cause a halt in the operation of the press and, through deenergizing of relay coil 62, to cause an operating or driving stroke of cylinder 28 to the extent limited by stop assembly 36a for effecting a corresponding skip feed. Of course, at the end of such driving stroke, limit switch 57 is closed to step stepping relay switch 52 to its fourth position.

d. Since the fourth stop selector switch 53-4 is shown with its movable contact 53a set to engage the RESET-"contact, the stepping of switch 52 to its fourth position will result in energizing of reset relay coil 52f,whereby poles 52a and 52b are returned to their first or initial positions for a repetition of the described cycle of operations.

Of course, if the fourth stop selector switch 53-4 had been set to engage its contact 53a with the STOP" contact, the stepping of switch 52 to its fourth position'would result in energizing of relay 60 to close its normally open contacts 60-1 and thereby cause circuit 61 to stop the operation of the press. Upon such stoppage, the perforated material may be removed either manually or by repeated manual operation of switch 63 to obtain repeated skip feeds. The skip feed apparatus can be conditioned to repeat the described cycle by displacing switch 58 to its RESET position and then to its ON position. After new material is inserted into the press, the press is restarted to perform the described cycle of operations.

Although the described cycle, with the settings shown on FIG. 5, has involved three skip feeds and a reset or stop operation, that is, a total of four steps in the sequence, it is apparent that the described sequence and control circuit can be set for a total of five skip feeds and a final reset or stop. It is further apparent that the number of steps in the stepping relay switch 52 may be either increased or decreased from the number shown with corresponding increase or decrease in the number of stop and count-selector switches so as to vary the capacity of the apparatus to provide complex patterns of perforations in the material operated upon by the press. In any case, for any step of the sequence it is possible with the described apparatus to select any one of four skip feed lengths and any one of four different numbers of rows of perforations between successive skip feeds, and the considerable number of variations in the perforating patterns that are thereby automatically obtainable may be further increased by increasing the number of stop as semblies and/or the number of counting devices.

Although an illustrative embodiment of the invention has been described in detail herein with reference to the drawings, it is to be understood that the invention is not limited to that precise embodiment, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.

We claim:

1. Apparatus for the skip feeding of material to an associated machine which operates to incrementally advance said material and to perform repetitive operations on the incrementally advanced material, said apparatus comprising driving means operative to effect skip feeding advance of the material to said machine, several selectively operative stop means which are individually located to determine respective skip feeding advances by said driving means, counting means to momentarily halt the operation of said machine upon the occurrence of predetermined numbers of said repetitive operations, means to operate said driving means upon each momentary halt in the operation of said machine, and sequencing means rendering said several stop means operative in a predetermined sequence for successive operations of said driving means, whereby the incremental advances of the material for said numbers of repetitive operations and the skip feeding advances of the material in accordance with said predetermined sequence of rendering operative said stop means result in a desired pattern of said repetitive operations on the material.

2. Apparatus according to claim 1; in which said driving means includes a cylinder having a ram displaced linearly by the action of fluid under pressure in said cylinder and means to convert linear displacement of said ram into skip feeding advance of the material through a distance determined by the length of stroke of said ram, and each of said stop means, when operative, correspondingly limits said length of stroke of the ram. 7

3. Apparatus according to claim 2, in which said stop means are individually adjustable in the direction of said linear displacement of the ram for varying the lengths of stroke of the ram limited by the respective stop means.

4. Apparatus according to claim 3, in which each of said stop means is movable generally perpendicular to the direction of said linear displacement of the ram between operative and retracted positions.

I 5. Apparatus according to claim 1, in: which said counting means includes a plurality of counting devices individually set so as to be operative to momentarily halt the operation of said machine upon the occurrence of respective numbers of said repetitive operations, and said sequencing means further renders said counting devices operative in a predetermined sequence for successive operations of said driving means,

whereby different numbers'of repetitive operations can be 'haltin theoperation of said machine to close said contacts in succession. and stop-selector switches-eachconnected with a respective one of said contacts of the steppingfrelay means to be energized upon closing of said respective contacts, each of said stop-selector switches having selectivelyfengageable contacts respectively connected with said so'lenoid means of said plurality of stop means so that, at each step of said stepping relay means, the stop means which is rendered operative is the one having its solenoid connected to the engaged contact of the stop-selector switch energized'throiigh the then closed contacts of said stepping relay means."

7. Apparatus according to claim 6,-i n which each of said stop-selector switches further has selectively engageable reset and stop contacts, and further comprising means to reset said stepping relay means upon energizing of a stop-selector switch having its said reset contact engaged, and means to stop the operation of said machine upon energizing ofa stop-selector switch having its said stop contact engaged.

8. Apparatus according to claim 6,inwhich saidcounting means includes means to produce electrical pulses in accordance with said repetitive operations of said machine and a plurality of counting devices operable bysaid pulses to mostepping relay means upon energizing of a stop-selector switch having its said reset contact engaged, and'means to stop the 7 operation of said machine upon energizing of a stop-selector switch having its said stop contact engaged.

10. in apparatus for feeding material to an associated machine which performs repetitive operations on the material, the combination of a cylinder havinga ram reciprocable by the action of fluid under pressure in said cylinder, means to feed the material in response to each reciprocation of the ram with the distance the material is fed being determined by the length of stroke of said ram, a plurality of selectively operative stop means which are individually located to correspondingly limit said length of stroke of the ram, and sequencing means rendering said stop means operative in a predetermined sequence for successive reciprocations of said ram.

11. Apparatus according-to claim 10, in which said stop means are individually adjustable in directions parallel to the reciprocation of said ram for varyingthe lengths of stroke of the ram limited by the respective sto means.

12. Apparatus according to claim 0,1n which said means to to adjust the location of the respectivestop means and a stop relay means having a plurality of contacts and being stepped mentarily halt the operation of said machinezupon the occurrence of respective numbersof saidrepe titive operations, said stepping relay means has a plurality of second contacts to successively transmit said pulses uponistepping of said relay.

means, and said sequencing means further-includes count selector switches each connected with a respective one 'of said second contacts of the relay means to receive said pulses from the respective second contacts when 'thelatter transmit the upon each reciprocation of said ram to close said contacts in succession, and stop selector switches each connected with a respective one'of said contacts of the stepping relay means to r be energized upon closing of said respective'contacts, each of said stop-selector switches having selectivelyengageable contacts respectively connected-with said solenoid means of said plurality of stop means so that, at each step of said stepping relay means, the stop member which is moved to its operative position is the one having its associated solenoid connected to the engaged contact of the stop-selector switch energized through the then closed contacts of said stepping relay means.

14. Apparatus according to claim l3,in which each of said stop-selector switches further has a selectively engageable reset contact, and said sequencing meansfurther has means to reset said stepping relay means in response to energizing of a stop-selector switch having its said reset contact engaged.

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